High Temperature Creep Behavior Of The Tc6 Titanium Alloy And The Effect Of Heat Treatment Process Of Alloy Organization Performance

TC6titanium alloy is a good overall performance of the martensitic α+β two-phase heat-strong titanium. It can long-term work in the400～450℃, and TC6alloy is mainly used for aero-engine blades, rotating parts and fasteners. In this paper, TC6alloys were systematically investigated by means of optical microscope, scanning electron microscope, transmission electron microscope, mechanical properties testing machine and tensile creep machine. The main contents and conclusions are as followings:(1) This article through the high temperature tensile creep experiments, obtained the TC6alloy creep strain-time curves, and the steady creep rate. The results show that the steady creep rate increases with the increase of temperature or stress. The creep parameters were obtained by the creep strain-time curves, as followed the high temperature tensile creep model were established:(2) The creep behavior of TC6alloy in the range of350～450℃is controlled by double mechanisms of dislocation and diffusion.; and in the range of350～450℃the creep behavior mechanism is mainly controlled by diffusion; and the boundary slip also has some effect to creep.(3) TC6titanium alloy in the process of the creep grain distortion stretched, dislocation density increases, the dynamic role in reply form and crystal structure, and along with the creep temperature and stress improve, dislocation density and the crystal structure more obvious.(4) TC6alloy creep under the high temperature of400℃, the number of secondary a phase compared to the number of other temperature creep significantly more. One is that the secondary elongated α-phase is mainly through the phase boundary of the a phase and β phase; another is that the secondary lath a-phase mainly exists in the β turned. Totally secondary a phase increased to increase the alloy’s high temperature creep resistance.(5) The isothermal annealing of (920℃/1.5h,FC+620℃/2h) for TC6alloy, the tensile strength, yield strength, elongation and reduction of area for the alloy are1032MPa,983MPa,20.2%,47.8%respectively, showing the best combination of strength and plasticity.